I am just getting started with Google Mock. The For Dummies is reasonably easy to follow.
However, I don't understand why the example has
class MockTurtle : public Turtle {
public:
...
MOCK_METHOD0(PenUp, void());
MOCK_METHOD0(PenDown, void());
MOCK_METHOD1(Forward, void(int distance));
MOCK_METHOD1(Turn, void(int degrees));
MOCK_METHOD2(GoTo, void(int x, int y));
MOCK_CONST_METHOD0(GetX, int());
MOCK_CONST_METHOD0(GetY, int());
};
There are multiple MOCK_METHOD0 and multiple MOCK_METHOD1, etc. Functions with similar signatures seem to get the same mock number, but documentation does not mention this, explaining the how & why, and the definitions are identical. How am I to know what to do?
So use ON_CALL by default, and only use EXPECT_CALL when you actually intend to verify that the call is made.
Using the Turtle interface as example, here are the simple steps you need to follow: Derive a class MockTurtle from Turtle . Take a virtual function of Turtle (while it's possible to mock non-virtual methods using templates, it's much more involved). In the public: section of the child class, write MOCK_METHOD();
In real system, these counterparts belong to the system itself. In the unit tests they are replaced with mocks. Gtest is a framework for unit testing. Gmock is a framework imitating the rest of your system during unit tests.
You must always put a mock method definition ( MOCK_METHOD* ) in a public: section of the mock class, regardless of the method being mocked being public , protected , or private in the base class. This allows ON_CALL and EXPECT_CALL to reference the mock function from outside of the mock class. (
In the How to Define It section, it is explained :
- In the public: section of the child class, write MOCK_METHODn(); (or MOCK_CONST_METHODn(); if you are mocking a const method), where n is the number of the arguments; if you counted wrong, shame on you, and a compiler error will tell you so.
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